Characterisation of phases and deformation temperature for additively manufactured shape memory polymer components fabricated from rubberised acrylonitrile butadiene styrene

Abstract

Integrating shape memory polymers into additive manufacturing processes enables a form of 4D printing where a printed part can be manipulated into varying geometries upon the application of external stimuli. The work here explores the raster pattern sensitivity of the shape memory properties of two iterations of a polymer blend system composed of thermoplastic rubber and acrylonitrile butadiene styrene. Tensile test specimens were fabricated in three different raster patterns through the use of material extrusion additive manufacturing and deformed at room (25°C), low (−40°C) and high temperatures (105 and 110°C). Shape memory parameters were assessed and the shape fixation ratio was found to exhibit a sensitivity to raster pattern when deformation occurred at room and low temperatures, while the shape recovery ratio was found to be sensitive to raster pattern when deformation occurred at elevated temperatures. The influence of phase content was also explored and a decrease in rubber content led to an improvement in shape memory properties. The alignment of polymer phases with print raster direction was also found to influence raster pattern sensitivity.